macknight



March 19, 19.57 E. W. MacKNlGHT Re. 24,290

ADJUSTABLE SEAT ASSEMBLY Original Filed Bapt. 5 1 950 FIG.

` INVENTOR EDGAR W. MucKNIGHT, DECEASED -ADMINISTRATRIX BY BONNAMQCKNIGHI BY ffm y 734m ATTORNEYS United States Patent-O ADJUSTABLE SEATASSEMBLY al No. 2 650 647 dated September 1 1.953, Serial 183,245:sefnember 5, 195o. Applicatie for re. issue August 29, 1955, Serial No.531,308

9 Claims. (Cl. 155-81) Matter enclosed in heavy brackets [jl appears inthe original patent but forms no part of this reissue spe cation; matterprinted in italics indicates the additions made by reissue.

[My] The invention relates to adjustables'eats and more particularly toa seat assembly for technici-ans such as dentists, to permit suchtechnicians to operate while comfortably seated, and constitutes animprovement upon the adjustable seat assembly forming the subject of[my] the prior lapplication for an Adjustable Seat Assembly, Serial No.87,277, filed April 13, 1949, now Patent No. 2,572,874 of October 30,1951.

Among the objects of [my] the invention are:

(l) To provide a novel and improved adjustable seat assembly,particularly for use by dentists or the like when working on patients;

(2) To provide a novel and improved adjustable seat assembly fordentists or the like, which will facilitate the approach and retreat ofan operator with respect to a. patient in a patients chair;

(3) To provide a novel and improved seat assembly for dentists, whichwill permit such dentist or the like to move with greater ease andcomfort to any desired posi- .tion with respect to a patient; (4) Toprovide a novel and improved seat assembly for dentists or the like,which will permit movement by the operator to any desired position withrespect to a patient, and afford such operator a stronger feeling ofAsecurity While operating on such patient.

Additional objects of [my] the invention will be brought out in thefollowing description of a preferred embodiment of the same taken inconjunction with the accompanying drawings wherein- Figure l is a viewin section of a seat assembly embodying the features of the presentinvention and illustrating the manner of tying the same in with apatients chair;

Figure 2 is a view in section, taken in the plane 2 2 'of Figure 1;

Figure 3 is a view in section, taken in the plane 3-3 ofv Figure 2; and

Figurey 4 is a View depicting a structural detail of the assembly ofFigure 1. j The invention, as illustrated in the drawings, includes a-wheel truck 1 involving a trough member 3 having depending side walls 5and 7, and between these side walls, adjacent each end of the troughmember, there is welded or otherwise affixed a depending yoke 9 formounting a Iwheel 11.

-A vertically disposed channel member 13, constitnt- I ing the outercomponent of an adjustable telescopic standard 15, has at its lower end,a cross arm in the form of "a shallow saddle 17 which straddles thetrough member of the wheel truck and is bolted thereto, therebyproviding firm anchorage 4for the vertical channel member.

This vertical channel supports a bracket 19 on which a tongue 21 may beslidably adjusted as to elevation, such bracket constituting a pair ofspaced bracket blocks 22 and 23 inserted within the channel member andwelded or ice 2 otherwise affixed thereto, and to the exposed ends ofthese two blocks, there is bolted a bracket plate 25 of a width suchthat its vertical edges extend slightly beyond th bracket blocks toeither side thereof. 1

The aforementioned tongue 21 involves a length of channel member,preferably slightly tapered for appearance sake, with its broad endtoward the bracket plate to which it is adjustably fixed for elevationaladjustments. This is accomplished by aftixing to each side of the tongueat its broad end, a clamping plate 27 which overhangs or extends beyondthe end of the tongue suiciently to permit of the formation of a groove29 adapted to receive an edge of the bracket plate. A clamping bolt 31passing through the tongue and clamping plates constitutes means fordrawing the clamping plates toward e-ach other for clamping the tongueto the bracket plate at any desired position along such bracket plate.

Such vertical adjustment of the tongue permits 'the seat yassembly to beaccommodated to chairs of different designs and styles, as placed on themarket by different manufacturers, thus enabling the tongue to clearoperating pedals, engine rheostat, etc., as well as the base flange ofthe patients chair, which allows the operator to move in close to thepatient.

At its narrow end, the tongue terminates in a pivot yoke 33 having itslegs lying in parallel horizontal planes, and perforated to receive avertically disposed clamping bolt 35.

The innerrnember of the telescopic standard constitutes a tube 37 whichcarries the seat 39 and associated mechanisrn 40. It is telescopicallysupported within the vertical channel member by providing alignedopenings in the bracket blocks 22, 23 of a size sufficiently to slidablyreceive the tube, and at the upper end of the vertical channel member,there is provided means 43 for locking such tube in any verticallyadjustedposition.

Such means comprises a rectangular housing of two sections, namely, alower section 45 which is integrally united to the upper end of thevertical channel member, and an upper section 47 which provides amatching tit with the lower section. The upper section is held to thelower section by a bolt 49, both sections having vertically alignedopenings to permit passage of the tube 37.

Within the housing is a locking plate 51 which has a central beveledopening therethrough, through which the tube may comfortably pass whensuch locking plate is in a horizontal position. At one end, this lockingplate is loosely supported between a shoulder 53 and a iiange 5S formedby suitably crimping a piece sheet metal and welding the same into thelower section of the housing, while at its opposite end, the plate isprovided with a. perforation through which the boit i9 passes, the platebeing normally urged downwardiy at this end, against the tube 37 by acompression spring 5'? thereubove. Disposed below the locking plateinline with the compression spring 57, is a Ilip 59 constituting one endof a lever 61, preferably in the forni of a stiff wir@ loop whichextends through a wall of the housing and fulci'uins on the edge of theopening through which it passes. Under the action of the compressionspring, the tube will, the absence of any opposing force, remain in itsprevailing adjustment, and any weight or pressure applied to the upperend of the tube, as when one sits uponL the scat, will only serve toenhance the binding eiicct oi the locking plate thereon.

When it is desired to adjust or change the elevational position ot' theseat which is carried on the tube, a downward pressure on the exposedend of the lever will lift the lower end of the locking plate, therebybringing the plate to a horizontal plane, whereby the tube will be freedfor movement along its vertica1 axis.

As previously indicated, the tube 37 carries the seat 3.9 and itsassociated mechanism 40. Such associated mechanism includes a rod orshaft 63 journaled in bearings 65, 67 disposed, one at each end of thetube. This shaft extends beyond the upper end of the tube and at thisend, lthere is ixedly mounted an arm 69 which terminates at its otherend in a bearing 71., in which is journalcd aA short shaft 73 whichprotrudes from the bearing at either end thereof. At its upper end, thisshort shaft has affixed thereto a seat arm 7S in the free end of whichis journaled the stem 77 of a suitable seat 39, spaced bear ings beingpreferably provided for this purpose,

As thus far described, the path of movement of the seat with respect tothe axis of the supporting tube, is indeterminable and not fixed. Thisis so because, under the circumstances, the seat is adapted to swingindiscriminately about the short shaft as an axis, while at the sametime, the short shaft is adapted to swing indiscriminately about theaxis of the supporting tube. Therefore, in order to pre-establish thepermissible path of movement of the seat with respect to the axis of thesupporting tube, both of the aforementioned swinging movements must becontrolled with respect to each other,

This [I accomplish] is accompiished by fixedly mounting on the upper endof the tube a sun gear 79, While at the lower end of the short shaft 73,[I provide] there is provided a planetary gear 81, and then [connect]connect- Ing the two gears by some drive means such as a chain drive 83.With such a connection, any swinging movement on the part of the shortshaft in an -arc about the axis of the supporting tube, will cause theseat to swing in an are in opposite direction about the short shaftaxis,

By selecting a proper relationship between the ratio of arm lengths andthe gear ratio, substantially linear movement of the seat may berealized and along a path through the axis of the supporting tube. Agear ratio of two to one between the sun gear and planetary gear willsatisfy .thercquiremenls, Where both arms are of the same length. Toassure that such linear movement shall be confined to a particulardirection, namely, along the axis of the tongue, which will then providefor linear movement toward and away from a patient, the seat and itsassociated mechanism should be initially assembled so that a linejoining the axis of the supporting tube and the center of the seat,sha-ll sight along the axis of the tongue, and to assure maintenance ofsuch directional adjustment, the sun gear must be fixed against rotationon its axis. This is accomplished by afxing a guide rib 85 along theback of the bracket plate and slidably engaging the same by aguide block87 aixed to the tube 37.

Extending upwardly from the sun gear, are a pair of stop pins 89, 91disposed on a line preferably slightly oi center. Such stop pins standin the path of movement of the planetary arm @and thus preclude theshort 'shaft from ever reaching a dead center position, which mightinterfere with smooth, effortless movement of the seat. Ease of movementof the seat between its forward-'and retracted positions will,therefore, alwaysbe assured.

A shroud 93 may be installed over the planetary gear arrangement and,when so installed, is held out of contact with the chain drive by a bolt95 extending through the planetary arm.

The entire seat assembly is designed for arcuate travel about the boltaxis located at the end of the tongue, and accordingly, to facilitatesuch movement, the truck wheel yoks' 9 are installed on a slight angleso as to'cause the4 wheels to describe an are about such pivot pointwithout drag. Means for fastening the seat assembly to a dental chairpreferably takes the form of a pivot post 103, provisionbeing made foranchoring the same to the `lower rim 1,05 of the base of the patient'schair by means of a suitable clamp. Such clamp may involve an arcuatetrough section'109 adapted to lit'over therir 0f the, chair hase,1leaving anexposedupper Ahorizontal ange "1 1`fto' which may be attachedone' end of the pivot post.' Such attach-ment is preferably by way of'a' ball and 12a-seo' socket connection, the rim being raised at the pgint ot connection to provide -a socket 113, while the pivot post, atits point of connection, having a tubular lower end 114 which isthreaded internally for the reception of la bolt 115 passing through theflange of the clamp, with its head fitting into the socket. Byconstricting the neck ol the bolt, a certain latitude of movement forthe pivot post will be permitted at this point.

By providing a lateral perforation through the lower end of the pivotpost to expose certain of the threads on the bolt, and then defo-rmingsuch threads with a suit-able tool, the pivot post connection to theclamp may be made permanent.

The pivot post is preferably made exten-sible by making it of telescopicparts, namely a pivoted tubular element 114 with a sleeve 119 slidabletheron, and then providing means for supporting the sleeve at differentelevational positions on the tubular element. Thiscan be readilyaccomplished by laterally perforating the pivoted element at spacedpoints longitudinally, and providing a pair of diametrically disposedopenings in the sleeve, which are adapted to line up with selectedperforations in the pivoted element. The perforations in the sleeve arepreferably of larger diameter than'the openings in the pivoted elementto receive the head and nut of a clamping bolt 123 passing through thealigned holes, whereby, upon tightening -the nut on such bolt, thetightening pressure will be applied solely to the pivoted element, andsuiciently to compress the same and cause corresponding expansionin lanormal direction against the sleeve, to thereby bind the same againstmovement with respect to the pivoted element.

At its upper end, the sleeve is closed except for a threaded axialopening for the reception of the pin or bolt 35. Such bolt is adapted topass through the per-V forations in the yoke at the end of the tongueprior to threading the bolt into the upper end of the sleeve forsecuring the seat assembly to the pivot post. A suitable spacing collar125 may be applied to the bolt for disposition between the spaced armsof the pivot yoke, toV rigidify the connection at this point, so thatall pivot movement will occur at the lower endl of the pivot post- 'I'heball and socket pivot connection of the pivot post to the clamp not onlyprovides fo-r the arcuate travel`- 'of the entire seat assemblyasindicated, but permits the se-at assembly to ride over obstructions orirregularities with; out transmitting undue strain to any part of thedevice.

Ordinarily, in the average installation, the weight of the patientschair on the lowerflange of 'the clamp will be suicicnt to hold the.pivot post installation in place, but in the event such chair should besusceptible to creeping, theupper flange ofthe clamp may be providedwith one or more threaded -openings 126. for the receptionof-'cl'a'mping screws which may be tightened. down against the rim ofthebase of thechair.

In accordance with the improved features ofthe present invention, [-Iprovide] there4 is provided means fo'rformally restraining movement ofthe sea-t from its retracted position, in. the absence, of anover-powering force-,wand such means preferably takesthe form of a' flatcoil spring 12,9 encirclingthe sun gear and having one end anchored insaid gear and its other end hooked around the lower end of the bolt 9,5,which is the same. as being anchored'to the planetary arm 69. The springis preferably disposed: a circumferential groove 131 formed in`thegear,4 by anchoring onev end of a. length of spring wire in a recessin a wall of such groove, wrapping such wirearound the gear and thenhooking its free end about the bolt` 95.

Any force. sufficient to overcome the resistance, offered by the spring,will causeA the seat to moveforward, the spring in the meantime being.wound tighter to build up fisieet4 tantissime Se' that P011 removal-atado erco ingiere@ theseatwill berkestoredftq its. retracted Unsere-rseauditivas agresor-assemble W be adjusted to a slight tilt angle with thever# tical, say of the order of 2 to 5 degrees, without the seatshifting from its retracted position. One Vof the advantages derivedfrom this relationship resides in the fact that the weight of theoperator on the seat will provide a component of force in the forwarddirection of its movement, thus facilitating the use of the seatassembly in carrying the operator toward the patient.

Working from a seat so tilted, places the operator in a more comfortableand relaxed posture, at the same time avoiding the necessity ofconsciously holding the seat against retraction by the spring, thusenabling the operator to work more effectively and eiciently.

From the above description of [my] the invention in its preferred form,it will become apparent that the same fulfills all the objects of [my]the invent-ion as previously stated, and while [I have described my] theinvention has been described in considerable detail, the same is subjectto alteration and modication without departing from the underlyingprinciples thereof, rand [L] therefore, [do not desire to be limited inmy protection] the protection sought should not be limited to suchdetails, except as may be necessitated by the appended claims.

[I claim] What is claimed is:

[1. An adjustable seat assembly comprising a wheel truck; a standardextending upwardly from said Wheel truck; a seat; means supporting saidseat on said standard for movement laterally thereof; means for holdingsaid standard at a slight tilt angle with the vertical; and meansnormally restraining movement of said seat in the direction of such tiltangle from a normal unoccupied position in the absence of anoverpowering force applied to said seat and adapted to restore said seatto its normal unoccupied position upon release of such force] [2. Anadjustable seat assembly comprising a wheel truck; a standard extendingupwardly from said wheel truck; a seat; means supporting said seat onsaid standard for movement laterally thereof; means for holding saidstandard at a slight tilt angle with the vertical; and spring meansnormally restraining movement of said seat in the direction of such tiltangle from a normal unoccupied position in the absence of anoverpowering force applied to said seat and adapted to restore said seatto its normal unoccupied position upon release of such force] 3. Anadjustable seat assembly comprising a wheel truck; a standard extendingupwardly from said wheel truck; a seat; means supporting said seat onsaid standard, said seat supporting means including a pair of arms,means connecting said arms for angular movement, one with respect to theother, means pivotally mounting said arms at the free end of one of themto said standard, and means at the free end of the other of said armsfor carrying said seat; means for holding said standard at a slight tiltangle with the vertical; and means normally restraining movement of saidseat in the direction of such tilt angle from a normal unoccupiedposition in the absence of an overpowering force applied to said seatand adapted to restore said seat to its normal unoccupied position uponrelease of such force.

4. An adjustable seat assembly comprising a wheel truck; a standardextending upwardly from said wheel truck; a seat; means supporting saidseat on said standard for movement laterally thereof, said seatSupporting means including a pair of arms, means connecting said armsfor angular movement, one with respect to the other, means pivotallymounting said arms at the free end of one ol. them to said standard, andmeans at the free end of the other of said arms for carrying said seat;means for holding said standard at a slight tilt angle with thevertical; and means normally restraining movement of said seat in thedirection of such tilt angle from a normal unoccupied position in theabsence of an overpowering force applied to said seat and adapted torestore said seat to its normal unoccupied position upon release of suchforce, said means including a coil spring, one end of which is in effectanchored to said standard and the other end to that arm which ispivotally connected to said standard.

5. An adjustable seat assembly comprising a wheel truck; a standardextending upwardly from said4 wheel truck; a seat; means supporting saidseat on said standard for movement laterally thereof, said seatsupporting means including a sun gear xedly mounted at the upper end ofsaid standard, a planetary arm pivotally mounted at one end on the axisof said sun gear and rotatable on such axis with respect to said sungear, a planetary gear journaled adjacent the free end of said planetaryarm in substantially the plane of said sun gear, a seat supporting arm,means rigidly connecting said seat sup porting arm at one end to saidplanetary gear axially thereof, and a drive connection between said sungear and said planetary gear involving a chain incircling both saidgears, means for holding said standard at a slight tilt angle with thevertical; and means normally restraining movement of said seat in thedirection of such tilt angle from a normal unoccupied position in theabsence of an overpowering force applied to said seat and adapted torestore said seat to its normal unoccupied position upon release of suchforce. p

6. An adjustable seat Aassembly comprising a wheel truck; a standardextending upwardly from said wheel truck; a seat; means supportingsaidseat on said standard for movement laterally thereof, said seatsupporting means including a sun gear xedly mounted at the upper end ofsaid standard, a planetary arm pivotally mounted at one end on the axisof said sun gear and rotatable on such axis with respect to said sungear, a planetary gear journaled adjacent the free end of said planetaryarm in substantially the plane of said sun gear, a seat supporting arm,means rigidly connecting said seat supporting arm at one end to saidplanetary gear axially thereof, and a drive connection between said sungear and said planetary gear involving a chain incircling both saidgears, means for holding said standard at a slight tilt angle with thevertical; and means normally restraining movement of said seat in thedirection of such tilt angle from its normal unoccupied position in theabsence of an overpowering force applied to said seat and adapted torestore said seat to its normal unoccupied position upon release of suchforce, said means including a coil spring, one end of which is anchoredto said sun gear and the other end to said planetary arm.

7. An adjustable seat assembly for pivotal connection to a patientschair, said adjustable seat assembly com prising a seat; a standard;means for holding said seat at a slight tilt angle from the horizontaland in the direction of such pivot connection when said seat assembly isinstalled; means supporting said sent on said standard for movementlaterally thereof along a path substantially radially o such pivotconnection in thc installed condition of said seal assembly; and meansnormally restraining said seat from movement in the direction of suchpivotal connection from o normally unoccupied position of said seat inthe absence of an overpowering force, and adapted to restore said seatto its normal unoccupied position upon release of such force.

8. An adjustable scat assembly for plvolal connection to a patientschair, said adjustable seat assembly comprising a seat; a standard;means for holding said seat at a slight till angle from the horizontaland in the dircction of such pivot connection when said seat assembly isinstalled; means supporting said seat on said standard for movementlaterally thereof along a path substantially radially of suc/l pivotconnection in. the installed condi tion of said seat assembly; andspring means normally restraining said seat from movement in thedirection of such pivotal connection from a normally unoccupied positionof said seat in the absence of an overpowering force, and adapted torestore said seat to its normal unoccupied position upon release of suchforce.

9. 'An adjustable-'seat assembly f'or 'use in confiscation with apatientschair comprising, in'c'ombination, in "a'r- 'cuate trough'se'ctio'n for engagement with the base 'of 'the p'a'tlent's chair, anarm, meansincluding a pivot between 'said arcuate trough section andsaid arm t0 enable said 'arm to swing in a predetermined path about saidpivot 'and the patient's chair, a member providing a rotatable seatingsurface, means between said arm and said seating surface for enablingmovement ofthe seating sttrface'to- 'ward and from the patients chairwhen a user seated on lthe seating surface applies a force on theseating surface in 'a direction toward the paiients chair, and means forretraciing the seating surface in a direction away from j'se'atingsurface toward and from the patients chair is :independent of thesvn/inging movement of said arm about ,r 'said pivot.

l11. An'adjustable seat assembly crm'tprisingI a standard; 'a seat;'means .vzipporting said seat on said standard, said seat supportingmeans including a -pair of arnts, Ameans "connecting saidv arms `jo'rangular movement, one with 4.

"respect to the other, vmeans pivotally mounting said arms kit the freeend of one of them t'o said standard, 'and Vll) means 'at th'e free'end-of the "other of'said 'arms for carrying said seat; means ,forholding-said'standard at-a slight 'tilt angle with the vertical; andmeans normally restrain- Refcrences'Cited in the le of this patent orthe original patent UNITED STATES PATENTS 201,823 Oaks Mar. 26, 1878271,511 Pullen Jan 30, 1883 604,417 Richardson May 24, 1898 972,472 RebeOct. 11, 1910 1,147,896 Schroeder July 27, 19'15 1,322,551 Efaw Nov. 25,1919 1,395,130 McClurd Oct. 25, 192.1 1,712,927 Martois May 1'4, 19292,087,932 Zola July 27, 1937 2,297,845 Templeton Oct. 6, l1942 2,345,163Vourath Mar. 2s, 1944 2,533,363 Donohoe Dec. 12, 1950 2,586,120Templeton Feb. 19, 195.2

